Unfortunately I learned the hard way about QT tanks. I lost all my existing fish to ICH when adding some newbies (but the newbies survived - go figure). I am now setting up an old 10g as a QT and was wondering about cycling it. Can I attach the HOB filter to the existing tank to get some bacteria started? Or is there a better way to cycle a new tank. I've tried to look up info on actually getting the cycle going and I don't see a thread that addresses that. So if this question has already been answered a million times, please forgive me.